An engine starting device described in Patent Document 1 has been known as an engine starting device to be used for a vehicle. In this conventional example, the engine starting device is formed by coupling an ignition switch to a housing accommodating a camshaft (rotational operation shaft).
The ignition switch is coupled by being fitted and held in a switch attachment part formed in the rear end of the housing, and elastic pieces are snap-locked on engagement portions of the housing to prevent the ignition switch from falling.
Moreover, the ignition switch is provided with press-fit ribs configured to come into pressure contact with the peripheries of opening portions bored in the sidewall of the switch attachment part. In this way, rattling after the fitting is reduced.